How to Create a shell script to test the telnet connection status - Page 2

yhcheong · #1 (**permalink**) 03-19-2009

Quote:

Originally Posted by ghostdog74

what version is your sun solaris OS?

The version is

SunOS 5.8 Generic_117350-38 sun4u sparc SUNW,Sun-Fire-V890

pludi · #2 (**permalink**) 03-19-2009

Please use [code ][/code] (sans the space) tags for source and listings, it's easier to read.

Quote:

Originally Posted by yhcheong

Code:

exec 3>/dev/tcp/${10.x.x.x}/2071
if [ $? -eq 0 ]
then
    echo "Telnet accepting connections"
else
    echo "Telnet connections not possible"
fi

bash: /dev/tcp/${10.x.x.x}/2071: bad substitution.

The ${MACHINE} that I used was in preparation for the loop that you'll need for that many machines (it's substituted by the value of the variable MACHINE)

Change it like this and try again

Code:

MACHINE=10.0.0.1 # Change to what ever you need
exec 3>/dev/tcp/${MACHINE}/2071
if [ $? -eq 0 ]
then
    echo "Telnet accepting connections"
else
    echo "Telnet connections not possible"
fi

yhcheong · #3 (**permalink**) 03-19-2009

Quote:

Originally Posted by pludi

Please use [code ][/code] (sans the space) tags for source and listings, it's easier to read.

The ${MACHINE} that I used was in preparation for the loop that you'll need for that many machines (it's substituted by the value of the variable MACHINE)

Change it like this and try again

Code:

MACHINE=10.0.0.1 # Change to what ever you need
exec 3>/dev/tcp/${MACHINE}/2071
if [ $? -eq 0 ]
then
    echo "Telnet accepting connections"
else
    echo "Telnet connections not possible"
fi

Hi,

Code:

MACHINE=10.2.191.100 
MACHINE=10.1.101.100 
MACHINE=10.3.181.100 
exec 3>/dev/tcp/${MACHINE}:2061
if [ $? -eq 0 ]
then
    echo "Telnet accepting connections"
else
    echo "Telnet connections not possible"
fi

and the result is below

Code:

bash-2.03$ MACHINE=10.2.191.100
bash-2.03$ MACHINE=10.1.101.100
bash-2.03$ MACHINE=10.3.181.100
bash-2.03$ exec 3>/dev/tcp/${MACHINE}:2061
bash: /dev/tcp/10.3.181.100:2061: Not a directory
bash-2.03$ if [ $? -eq 0 ]
> then
>     echo "Telnet accepting connections"
> else
>     echo "Telnet connections not possible"
> fi
Telnet connections not possible

Sorry, please guide me.
Many Thanks

ghostdog74 · #4 (**permalink**) 03-19-2009

not guaranteed to work, but you can try

Code:

# sleep 3 | telnet somewhere portnumer

use grep or awk to grab messages to confirm connection or refusal

pludi · #5 (**permalink**) 03-19-2009

Quote:

Originally Posted by yhcheong

Code:

MACHINE=10.2.191.100 
MACHINE=10.1.101.100 
MACHINE=10.3.181.100 
exec 3>/dev/tcp/${MACHINE}/2061
if [ $? -eq 0 ]
then
    echo "Telnet accepting connections"
else
    echo "Telnet connections not possible"
fi

If you copy and paste, do so correctly. It's /dev/tcp/<machine>/<port>. The seperator is always the forward slash.
And you might want to start with some basic texts about shell programming, because that is not how you construct a loop (except maybe if you can create a DWIMTD function). There's a good introduction available here. It's written for Linux, but there are very few specific things used, most applies to any platform that bash runs on.

Code:

MACHINES="10.2.191.100 10.1.101.100 10.3.181.100"
for MACHINE in ${MACHINES}
do
    exec 3>/dev/tcp/${MACHINE}/2061
    if [ $? -eq 0 ]
    then
        echo "${MACHINE}: Telnet accepting connections"
    else
        echo "${MACHINE}: Telnet connections not possible"
    fi
done

pludi · #6 (**permalink**) 03-19-2009

/dev/tcp/... isn't a directory on any UNIX system that I know of, but a hint for bash to open a TCP connection and use it as a file handle. If bash complains about it that probably means that this functionality isn't supported.

yhcheong · #7 (**permalink**) 03-19-2009

Quote:

Originally Posted by pludi

/dev/tcp/... isn't a directory on any UNIX system that I know of, but a hint for bash to open a TCP connection and use it as a file handle. If bash complains about it that probably means that this functionality isn't supported.

I have check the the directory under dev. The TCP is exist. Hmm, any idea other than bash?
THanks!

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